1 /* 2 * kernel/power/suspend.c - Suspend to RAM and standby functionality. 3 * 4 * Copyright (c) 2003 Patrick Mochel 5 * Copyright (c) 2003 Open Source Development Lab 6 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. 7 * 8 * This file is released under the GPLv2. 9 */ 10 11 #include <linux/string.h> 12 #include <linux/delay.h> 13 #include <linux/errno.h> 14 #include <linux/init.h> 15 #include <linux/console.h> 16 #include <linux/cpu.h> 17 #include <linux/syscalls.h> 18 #include <linux/gfp.h> 19 #include <linux/io.h> 20 #include <linux/kernel.h> 21 #include <linux/list.h> 22 #include <linux/mm.h> 23 #include <linux/slab.h> 24 #include <linux/suspend.h> 25 #include <linux/syscore_ops.h> 26 #include <trace/events/power.h> 27 28 #include "power.h" 29 30 const char *const pm_states[PM_SUSPEND_MAX] = { 31 [PM_SUSPEND_STANDBY] = "standby", 32 [PM_SUSPEND_MEM] = "mem", 33 }; 34 35 static const struct platform_suspend_ops *suspend_ops; 36 37 /** 38 * suspend_set_ops - Set the global suspend method table. 39 * @ops: Pointer to ops structure. 40 */ 41 void suspend_set_ops(const struct platform_suspend_ops *ops) 42 { 43 mutex_lock(&pm_mutex); 44 suspend_ops = ops; 45 mutex_unlock(&pm_mutex); 46 } 47 48 bool valid_state(suspend_state_t state) 49 { 50 /* 51 * All states need lowlevel support and need to be valid to the lowlevel 52 * implementation, no valid callback implies that none are valid. 53 */ 54 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state); 55 } 56 57 /** 58 * suspend_valid_only_mem - generic memory-only valid callback 59 * 60 * Platform drivers that implement mem suspend only and only need 61 * to check for that in their .valid callback can use this instead 62 * of rolling their own .valid callback. 63 */ 64 int suspend_valid_only_mem(suspend_state_t state) 65 { 66 return state == PM_SUSPEND_MEM; 67 } 68 69 static int suspend_test(int level) 70 { 71 #ifdef CONFIG_PM_DEBUG 72 if (pm_test_level == level) { 73 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n"); 74 mdelay(5000); 75 return 1; 76 } 77 #endif /* !CONFIG_PM_DEBUG */ 78 return 0; 79 } 80 81 /** 82 * suspend_prepare - Do prep work before entering low-power state. 83 * 84 * This is common code that is called for each state that we're entering. 85 * Run suspend notifiers, allocate a console and stop all processes. 86 */ 87 static int suspend_prepare(void) 88 { 89 int error; 90 91 if (!suspend_ops || !suspend_ops->enter) 92 return -EPERM; 93 94 pm_prepare_console(); 95 96 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE); 97 if (error) 98 goto Finish; 99 100 error = usermodehelper_disable(); 101 if (error) 102 goto Finish; 103 104 error = suspend_freeze_processes(); 105 if (!error) 106 return 0; 107 108 suspend_thaw_processes(); 109 usermodehelper_enable(); 110 Finish: 111 pm_notifier_call_chain(PM_POST_SUSPEND); 112 pm_restore_console(); 113 return error; 114 } 115 116 /* default implementation */ 117 void __attribute__ ((weak)) arch_suspend_disable_irqs(void) 118 { 119 local_irq_disable(); 120 } 121 122 /* default implementation */ 123 void __attribute__ ((weak)) arch_suspend_enable_irqs(void) 124 { 125 local_irq_enable(); 126 } 127 128 /** 129 * suspend_enter - enter the desired system sleep state. 130 * @state: state to enter 131 * 132 * This function should be called after devices have been suspended. 133 */ 134 static int suspend_enter(suspend_state_t state) 135 { 136 int error; 137 138 if (suspend_ops->prepare) { 139 error = suspend_ops->prepare(); 140 if (error) 141 goto Platform_finish; 142 } 143 144 error = dpm_suspend_noirq(PMSG_SUSPEND); 145 if (error) { 146 printk(KERN_ERR "PM: Some devices failed to power down\n"); 147 goto Platform_finish; 148 } 149 150 if (suspend_ops->prepare_late) { 151 error = suspend_ops->prepare_late(); 152 if (error) 153 goto Platform_wake; 154 } 155 156 if (suspend_test(TEST_PLATFORM)) 157 goto Platform_wake; 158 159 error = disable_nonboot_cpus(); 160 if (error || suspend_test(TEST_CPUS)) 161 goto Enable_cpus; 162 163 arch_suspend_disable_irqs(); 164 BUG_ON(!irqs_disabled()); 165 166 error = syscore_suspend(); 167 if (!error) { 168 if (!(suspend_test(TEST_CORE) || pm_wakeup_pending())) { 169 error = suspend_ops->enter(state); 170 events_check_enabled = false; 171 } 172 syscore_resume(); 173 } 174 175 arch_suspend_enable_irqs(); 176 BUG_ON(irqs_disabled()); 177 178 Enable_cpus: 179 enable_nonboot_cpus(); 180 181 Platform_wake: 182 if (suspend_ops->wake) 183 suspend_ops->wake(); 184 185 dpm_resume_noirq(PMSG_RESUME); 186 187 Platform_finish: 188 if (suspend_ops->finish) 189 suspend_ops->finish(); 190 191 return error; 192 } 193 194 /** 195 * suspend_devices_and_enter - suspend devices and enter the desired system 196 * sleep state. 197 * @state: state to enter 198 */ 199 int suspend_devices_and_enter(suspend_state_t state) 200 { 201 int error; 202 203 if (!suspend_ops) 204 return -ENOSYS; 205 206 trace_machine_suspend(state); 207 if (suspend_ops->begin) { 208 error = suspend_ops->begin(state); 209 if (error) 210 goto Close; 211 } 212 suspend_console(); 213 suspend_test_start(); 214 error = dpm_suspend_start(PMSG_SUSPEND); 215 if (error) { 216 printk(KERN_ERR "PM: Some devices failed to suspend\n"); 217 goto Recover_platform; 218 } 219 suspend_test_finish("suspend devices"); 220 if (suspend_test(TEST_DEVICES)) 221 goto Recover_platform; 222 223 error = suspend_enter(state); 224 225 Resume_devices: 226 suspend_test_start(); 227 dpm_resume_end(PMSG_RESUME); 228 suspend_test_finish("resume devices"); 229 resume_console(); 230 Close: 231 if (suspend_ops->end) 232 suspend_ops->end(); 233 trace_machine_suspend(PWR_EVENT_EXIT); 234 return error; 235 236 Recover_platform: 237 if (suspend_ops->recover) 238 suspend_ops->recover(); 239 goto Resume_devices; 240 } 241 242 /** 243 * suspend_finish - Do final work before exiting suspend sequence. 244 * 245 * Call platform code to clean up, restart processes, and free the 246 * console that we've allocated. This is not called for suspend-to-disk. 247 */ 248 static void suspend_finish(void) 249 { 250 suspend_thaw_processes(); 251 usermodehelper_enable(); 252 pm_notifier_call_chain(PM_POST_SUSPEND); 253 pm_restore_console(); 254 } 255 256 /** 257 * enter_state - Do common work of entering low-power state. 258 * @state: pm_state structure for state we're entering. 259 * 260 * Make sure we're the only ones trying to enter a sleep state. Fail 261 * if someone has beat us to it, since we don't want anything weird to 262 * happen when we wake up. 263 * Then, do the setup for suspend, enter the state, and cleaup (after 264 * we've woken up). 265 */ 266 int enter_state(suspend_state_t state) 267 { 268 int error; 269 270 if (!valid_state(state)) 271 return -ENODEV; 272 273 if (!mutex_trylock(&pm_mutex)) 274 return -EBUSY; 275 276 printk(KERN_INFO "PM: Syncing filesystems ... "); 277 sys_sync(); 278 printk("done.\n"); 279 280 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]); 281 error = suspend_prepare(); 282 if (error) 283 goto Unlock; 284 285 if (suspend_test(TEST_FREEZER)) 286 goto Finish; 287 288 pr_debug("PM: Entering %s sleep\n", pm_states[state]); 289 pm_restrict_gfp_mask(); 290 error = suspend_devices_and_enter(state); 291 pm_restore_gfp_mask(); 292 293 Finish: 294 pr_debug("PM: Finishing wakeup.\n"); 295 suspend_finish(); 296 Unlock: 297 mutex_unlock(&pm_mutex); 298 return error; 299 } 300 301 /** 302 * pm_suspend - Externally visible function for suspending system. 303 * @state: Enumerated value of state to enter. 304 * 305 * Determine whether or not value is within range, get state 306 * structure, and enter (above). 307 */ 308 int pm_suspend(suspend_state_t state) 309 { 310 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX) 311 return enter_state(state); 312 return -EINVAL; 313 } 314 EXPORT_SYMBOL(pm_suspend); 315